This invention relates to apparatus for attaching a sounding balloon to a device which is adapted to be connected to a radiosonde by a flexible connecting element.
Meteorological or other similar radiosondes are lifted aloft by so-called sounding balloons which are filled with a lighter-than-air gas. As the sounding balloon ascends, the atmospheric conditions in the regions trailing the path of the ascending balloon change to at least some degree and for this reason it is customary to suspend the radiosonde from the sounding balloon by a relatively long flexible connecting element, such as a string, the length of which may be, for example, about 50 m. In this manner, any changes in the meteorological conditions caused by the ascending sounding balloon will not be detected by the radiosonde which has been situated a sufficient distance from the balloon to allow steady state atmospheric conditions to return.
Since the sounding balloon and the sounding apparatus must be released to rise simultaneously, it has been conventional to affix below the balloon mechanical means such, for example, as a pendulum mechanism or a friction brake, which allows the flexible connecting element to be payed out or discharged at a certain rate from a reel under the balloon. Such mechanical means have relatively complicated constructions and are therefore relatively expensive. However, since this equipment is disposable, it will be understood that it is of importance to be able to provide means for controllably releasing the flexible connecting element which is relatively simple in construction yet reliable in operation.
In applicant's Finnish publicizing print no. 64 013, a means for releasing the flexible connecting element attachable to a sounding balloon is disclosed which is simple in construction but which insures positive and uniform release of the connecting element. The releasing means comprises a plate-like body attachable to the sounding balloon and on which the connecting element is wound.
In using the connecting element release means disclosed in Finnish publicizing print no. 64 013, the filling tube of the sounding balloon is fixed within a slot provided at the upper end of the plate-like body whereupon the filling tube is folded back against itself and tied closed by a string. However, this arrangement has the drawback that the attaching and tube closing operations are quite time consuming and a reliable attachment of the releasing means to the sounding balloon is not always achieved, especially since the sizes of sounding balloons and the diameters of the filling tubes thereof vary over a relatively large range. Although it would be possible to use different releasing means for sounding balloons of different sizes and for filling tubes of different diameters, this will of course involve increased costs.
It is also known to use separate shut-off valves in the filling tubes of sounding balloons. However, the use of such separate shut-off valves is costly in view of the disposable nature of the apparatus.